Thioredoxin-Linked Changes in Enzymes and Storage Proteins

该建议基于最近的证据，即NADP/硫氧还蛋白系统（由硫氧还蛋白h、NADP-硫氧还蛋白还原酶和NADPH组成）在种子萌发中起作用。 硫氧还蛋白特异性地减少谷物的主要储藏蛋白（小麦中的麦醇溶蛋白和麦谷蛋白），从而增强它们的溶解度和对蛋白酶的敏感性，并还原性地使抑制淀粉酶（淀粉降解酶）的二硫化物蛋白失活（大麦淀粉酶/枯草杆菌蛋白酶抑制剂）。 这项研究的扩展表明，硫氧还蛋白系统加强了面筋蛋白网络，从而提高面包质量，并使胰蛋白酶抑制剂蛋白失活，从而潜在地改善大豆的营养品质。 一项涵盖这些发现的专利申请已经提交，硫氧还蛋白技术的商业化前开发已经开始。 这项研究提出了一些基本的新问题：（1）硫氧还蛋白在小麦等谷物的萌发过程中是否具有额外的调节功能？(2)硫氧还蛋白在发芽过程中的氧化还原状态和丰度发生了什么变化？(3)还原硫氧还蛋白所必需的酶的活性在发芽过程中是否发生变化？(4)硫氧还蛋白在其他类型种子（如大豆）的萌发中是否起作用？ 该研究将有助于加深对硫氧还蛋白功能、酶调控和种子萌发的认识。 %这项提议源于我们的研究，其中我们提出了一种酶系统（“硫氧还蛋白系统”）的证据，该系统作为已知最早的触发谷物（如小麦）发芽的信号发挥作用。 硫氧还蛋白系统通过以下方式起作用：（1）活化谷粒的贮藏蛋白，从而使它们能够被幼苗用作氮和能量的来源，以及（2）活化淀粉降解所需的酶，从而增强萌发早期的能量产生。 本研究的扩展表明硫氧还蛋白系统具有技术价值。 应用该系统的面粉增强面筋和提高面包品质。 硫氧还蛋白系统也中和动物消化酶的植物蛋白抑制剂。 将硫氧还蛋白系统应用于大豆等食品可以提高其营养品质。 一项涵盖这些用途的专利申请已经提交，硫氧还蛋白技术的商业化前开发已经开始。 目前的项目代表了这项研究的基本方面的延伸。 计划的实验将显示硫氧还蛋白系统是否在小麦中具有额外的功能，以及该系统是否在其他种子类型的萌发中很重要。 ***

Buchanan 9316496 This proposal is based on recent evidence that the NADP/thioredoxin system (consisting of thioredoxin h, NADP-thioredoxin reductase and NADPH) functions in seed germination. Thioredoxin specifically reduces major storage proteins of cereals (gliadins and glutenins in wheat), thereby enhancing their solubility and susceptibility to proteinases, and reductively inactivates a disulfide protein that inhibits alpha-amylase, an enzyme of starch degradation (barley alpha-amylase/subtilisin inhibitor). An extension of this research has shown that the thioredoxin system strengthens the gluten protein network, thereby enhancing bread quality, and inactivates trypsin inhibitor proteins, thereby potentially improving the nutritional quality of soybean. A patent application covering these findings has been filed, and precommercial development of thioredoxin technology has commenced. The proposed research addresses fundamental new questions: (1) Does thioredoxin have additional regulatory functions in the germination of cereals such as wheat? (2) What changes in redox state and abundance does thioredoxin undergo during germination? (3) Does the activity of enzymes necessary for the reduction of thioredoxin change during germination? (4) Does thioredoxin function in the germination of other types of seeds such as soybean?. The research will add to our understanding of thioredoxin function, enzyme regulation and seed germination. %%% This proposal stems from research in which we have presented evidence for an enzyme system (the "thioredoxin system") that functions as the earliest known signal triggering the germination of cereals such as wheat. The thioredoxin system functions by (1) activating storage proteins of the grain, thereby enabling their use as a source of nitrogen and energy by the seedling, and (2) activating enzymes required for the degradation of starch, thereby enhancing energy production in the early phase of germination. An extension of this research indicates that the thioredoxin system is of technological value. Application of the system to flour strengthens gluten and enhances bread quality. The thioredoxin system also neutralizes plant protein inhibitors of animal digestive enzymes. Application of the thioredoxin system to foods like soybean may enhance their nutritional quality. A patent application covering these uses has been filed, and precommercial development of thioredoxin technology has commenced. The current project represents an extension of the fundamental aspects of this research. The experiments planned will show whether the thioredoxin system has additional functions in wheat and whether the system is important in the germination of other seed types. ***